Blockchains that use proof-of-stake (PoS) variants allow you to earn additional coins by staking your coins. In exchange for helping secure the network and locking up your capital, you receive a proportional amount of the coin’s inflation. There are many PoS coins that each differ in their implementation and rewards — this site provides a long list of all of them and links to their respective specifics. A specific type of PoS is delegated proof-of-stake (DPoS), in which people vote for delegates, rather than directly staking as individuals. Staking rewards tend to be a bit higher in DPoS coins such as Ark and Lisk.
The amount of initial setup ranges between coins; some require you to set up a consistently-online node, whereas others, such as Ark, require only a one-time setup through a wallet. Node staking is often more lucrative than simpler methods, at the expense of being more time-consuming and requiring a larger amount to stake. Assuming you want a more passive method, Ark’s staking can provide ~10% return with virtually no setup besides owning coins and choosing a delegate.
Several exchanges such as Kucoin and COSS have tokens that allow you to receive a share of the fees collected by the exchange. Typically, a certain percent of the exchange’s collected fees are given back to token holders, and then within that portion, your received dividends are proportional to the amount of tokens you hold. This method is not necessarily very consistent, as it depends on exchange volume during a given period of time. However, if you are able to buy an exchange’s coin before it gains a lot of volume, you can end up earning a very high rate of return due to the token price initially being low. Note that this works in the opposite direction as well; if an exchange’s volume decreases, you may lose money in terms of both token price and dividends. Also note that these dividends may come in the form of coins on the exchange rather than in the exchange coin. This means that if you only hold a small amount of the exchange coin, you may receive amounts of each individual coin on the exchange that are too small to actually sell.
Some coins offer dividends in the form of other coins simply for holding the original coin. For example, NEO generates Gas, and Vechain will generate THOR. Typically, each unit of the original coin will generate some predetermined amount of the new coin. These new coins are related to paying network fees, whereas the original coins can be thought of more as equity in the network. The rate of return on these methods is quite low (~3% for NEO’s Gas), but they require no work beyond owning the original coin, so it is a very passive, low-risk method of earning income.